Microbiology Chapter4

If E. coli is moving up an attractant gradient, which of the following will happen? - CheA will autophosphorylate - levels of CheY-P will increase - short runs and a lot of tumblingIncorrect - long runs with no tumbling - none of the above

none of the above

Gram-negative bacteria

outer cell membrane, thin peptidoglycan layer, and cell membrane

Microenvironments are created within the biofilm based on

oxygen gradient nutrient concentration pH gradient

Which of the following proteins have antagonistic functions?

CheR and CheB-P

Metabolism

Chemical reactions that synthesize new cell components or release energy that drives cellular reproduction. Supported and regulated by enzymes.

True or False: The thinner peptidoglycan layer of gram-positive bacteria allows the crystal-violet-iodine complex to leave the cell

False

True or False: The presence of flagella can be determined by a Gram stain

False

Polar

Flagella attached at one or both ends of the cell

Amphritrichous

Flagella on both poles of the cell.

Lophotrichous

Groups of flagella originating from the same point on the cell.

Please select all of the characteristics that define life and living things. 1. Heredity 2. Sexual Reproduction 3. Growth and Development 4. Use of energy 5. Increase in size

Heredity, Growth and development, Increase in size.

Growth

Increase in size of population by reproduction. Enlargement of a single organism through maturation.

cytoskeleton

This structure is a network of protein polymers that helps stabilize the shape of the cell from within.

granules

This structure stores inorganic compounds, such as sulfur and polyphosphate

inclusion bodies

This structure stores nutrients during periods of ample resources to compensate for times when nutrients are scarce

Heredity

Transmission of an organism's genome by way of chromosomes.

Counterclockwise rotation of flagella causes runs, while clockwise rotation causes tumbles.

True

Mycoplasma pneumoniae lacks a cell wall and is termed pleomorphic.

True

Spirillum is a genus of spiral-shaped bacteria that move by flagella.

True

Rod-shaped bacteria

can be either gram-positive or gram-negative

The molecule primarily responsible for the strength and stability of the bacterial cell wall is

peptidoglycan.

A taxonomical outline of bacterial species based on shared evolutionary histories would be described as a

phylogenetic system.

Choose the answer that best completes this statement's blanks in the correct order. When all the flagella on a cell rotate in a counterclockwise fashion, the cell is propelled forward in a movement known as a ____, but when the flagella reverse direction, the cell stops and changes course in an action known as a ____.

run; tumble

Chemical and light stimuli

Chemotaxis, phototaxis

Please select all of the characteristics that define life and living things.

- the ability to synthesize new cell components or release energy through chemical reactions - ability to respond to their environment - ability to control the flow of some materials across cell boundaries

The staining process

1. Crystal violet 2. Rinsed with water 3. Gram's iodine 4. Rinse 5. Ethanol or acetone (differential) 6. Rinse 7. Safrin 8. Rinsed and dried

Order from the innermost to the outmost compartment. - Cell Wall -Cell membrane -Glycocalyx -Cytoplasmic matrix

1. Cytoplasmic matrix 2. Cell membrane 3. Cell wall 4. Glycocalyx

Peritrichous

flagella all over

Development

Includes all changes over the life span.

hook

curved sheath

Diploccus

Pairs of spherical cells

The best understood bacterial cytoskeletons are composed primarily of

Actin

After Gram's iodine is added, what color do the cells appear under a light microscope

All cells appear purple.

Which is correct? - Clostridium - spore-forming rod - Corynebacterium - club-shapeIncorrect - Vibrio - curved rod - Clostridium - spore-forming rod; - Corynebacterium - club-shape - All correct

All correct

What clues were the most important in arriving at the diagnosis of endocarditis? Fever of unknown origin Increased heart rate and breathing History of valve replacement Heart murmurIncorrect

All of them

Reproduction

All organisms use asexual reproduction using fission or mitosis.

Why was the physician's knowledge of an artificial heart valve important to the continued treatment of Mr. Jones?

Artificial valves readily support the growth of biofilms containing pathogenic bacteria.

Which of the following surfaces have nutrients available that encourage the development of biofilms? A)Dry abiotic surfaces B)Moist abiotic surfaces C)Moist abiotic surfaces and biotic surfaces such as plant and animal tissue D)Biotic surfaces such as plant and animal tissue

C) Moist abiotic surfaces and biotic surfaces such as plant and animal tissue

The cell envelope is the external covering that lies outside of the cell cytoplasm and is composed of the _______ and _______.

Cell membrane and cell wall

ribosome

Composed of RNA and protein, this structure synthesizes new proteins.

Flagella (1)

Composed of a filament, hook and basal body, these cell appendages provide movement for the cell.

Which of the following statements about the E. coli methyl-accepting chemotaxis proteins is TRUE? - They are found in the cell wall. - They are directly connected to the flagellum. - They interact with the CheW and CheA. - They are found in the cell wall and they are directly connected to the flagellum. - They are found in the cell wall, they are directly connected to the flagellum and they interact with the CheW and CheA.

Correct

Cell Wall Functions

Determines cell shape Prevents lysis

True or False: All bacteria can be classified as either gram-positive or gram-negative

False

True or False: Bacteria are larger than human cells.

False

True or False: Bacteria are only visible with an electron microscope.

False

True or False: Biofilms are composed of a single bacterial species

False

Responsiveness

Irritability, communication, or movement

Pili

Made up of pilin protein. Function to join bacterial cells for partial DNA transfer called conjugation. Only in Gram-negative

Glycocalyx

Made up of sugars/proteins. Slime or capsule. - Protect from dehydration. - Inhibit killing by white blood cells (Phagocytosis) - (pathogenicity). - Attachment: Formation of Biofilms.

If the Gram's iodine step was skipped in this technique, what would likely be seen under the microscope?

Most cells would appear red/pink

What was the significance of the prior MRSA skin infection?

Mr. Jones needed to be treated for another drug-resistant infection with multiple powerful antibiotics

Why must fresh cells be used when performing a Gram stain

Old cells may not Gram stain properly

Monotrichous

One flagellum attached to one end of the cell.

Diseases caused by obligate intracellular bacteria include

Rocky Mountain spotted fever endemic typhus

Which of the following statements about flagellar structure is TRUE? - The hook anchors the flagellum in the cell membrane. - The basal body is a short curved segment. - The filament extends out of the cell. - The hook anchors the flagellum in the cell membrane and the basal body is a short curved segment. - All correct

The filament extends out of the cell.

Why was the penicillin that was prescribed during Mr. Jones first doctor's visit ineffective in treating the infection?

The infectious agent was resistant to the drug.

chromosome

The structure which contains the essential DNA of the cell

plasmid

The structure which contains the nonessential DNA of the cell.

Transport

The system of controlling the flow of material

Axial Filaments

These long, coiled threads provide movement to spirochetes. Periplasmic, internal flagella, enclosed between cell wall and cell membrane of spirochetes. Movement by contracting, twisting, and flexing.

Fimbrae

These short, bristle-like projections are used to attach the cell to other cells or surfaces.

Which of the following explains why archaeons are extremophiles?

They are ancient, primitive organisms that adapt well to extreme conditions because they have retained characteristics of the cells that first evolved when Earth's conditions were far more extreme.

Which of the following statements about the E. coli methyl-accepting chemotaxis proteins is TRUE?

They interact with the CheW and CheA.

The two groups of obligate intracellular bacteria are the ________, usually spread by contact, and the ________, usually transmitted by the bites of arthropods.

chlamydias; rickettsias

Microbial biofilms like the one seen here in Mr. Jones' case are the cause of the majority of ______ infections.

chronic

Excess nutrients that the cell may store for later use may be found within

cytoplasmic granules.

What general type of stain is used to separate types of bacteria based on their cellular structures?

differential

The differential stage of the Gram stain is the application of _____.

ethanol

The production of which substance leads to thickening of the biofilm over time?

exopolymer

Which of the following structures leads to reversible binding of bacterial cells to a surface?

fimbriae and flagella

filament

long, thin, helical structure composed of protein flagellin

Other than maintaining the shape of the cell, what is the primary function of the cell wall, and which component contributes most to this function?

maintaining strength; peptidoglycan

Bacterial species are defined in a fundamentally different way than mammalian species are. This is because

mammals reproduce sexually while bacteria reproduce asexually.

Which of the following surfaces have nutrients available that encourage the development of biofilms?

moist abiotic surfaces and biotic surfaces such as plant and animal tissue Correct

Spirochetes

move by axial fibrils

The cell membrane is composed of _____________.

proteins dispersed throughout a phospholipid bilayer

When ethanol is applied correctly, gram-positive cells appear ____ and gram-negative cells appear ____

purple; colorless

The _______ level of bacterial organisms refers to a group of organisms that all share the same traits while the subspecies level refers to the variation or differences of individual cells within that group.

species

basal body

stack of rings firmly anchored in cell wall

The term used to describe a cluster of spherical bacteria is _________

staphylococci

What most likely killed Mr. Jones?

stroke due to blockage by loosened piece of biofilm

Gram-positive bacteria

thick cell wall composed primarily of peptidoglycan and cell membrane. - teichoic acid and lipoteichoic acid

The primary function of the cell membrane is

to regulate the transport of molecules in and out of the cell.